They take an adeno-associated virus — a virus which is usually present in humans but not known to cause disease — remove most of its genes and patch a shiny, new, properly functioning version of the rpe65 gene into it.

In collaboration with my colleague Jörg Schlehofer, we were also able to demonstrate that herpes simplex virus, but also other herpes -, adeno -, and vaccinia virus infections of polyoma - or papillomavirus DNA harbouring cells, resulted in amplification of the DNA of the latter.

They include canine distemper virus, RAV7 and MAM1 avian viruses, the Borna virus in rats – which is also linked with depression in humans, types of scrapie, three adeno viruses including AD5, AD36 and AD37 which cause fat gain in several species, and chlamydia pneumonae bacteria.